Blowing agents for thermoplastic compositions

Abstract

The present invention is directed to derivatives of azoles, their preparation and their use as chemical blowing agents for thermoplastic molding compositions. The agents of the invention are characterized in their improved compatibility with the resin wherein they are incorporated.

What is claimed is: 
     
       1. A molding composition comprising (a) a thermoplastic resin and (b) about 0.1 to about 25% relative to the weight of said (a) plus (b) of a chemical blowing agent characterized in that its molecular structure contains at least one pentatomic heterocyclic ring and conforms to ##STR20## wherein A and A' are moieties which do not negate the foaming ability of said (b) and which do not contribute to the degradation of said (a) upon foaming. 
     
     
       2. The composition of claim 1 wherein said (a) is a polycarbonate. 
     
     
       3. The composition of claim 2 wherein polycarbonate is a homopolycarbonate based on bisphenol A. 
     
     
       4. The composition of claim 1 wherein said (a) is polyalkylene terephthalate. 
     
     
       5. The composition of claim 4 wherein said polyalkylene terephthalate is polyethylene terephthalate. 
     
     
       6. The composition of claim 1 wherein said (b) is selected from the group consisting of compounds having the formula ##STR21## wherein R 1  is a C 6  -C 16  aryl, a C 1  -C 32  alkyl, or a C 2  -C 12  alkenyl, and R 2  is a C 1  -C 20  alkyl, C 7  -C 20  alkaryl, trialkylsilyl, a hydrogen atom, an alkali metal or ##STR22##  where A is C 1  -C 12  alkyl or C 6  -C 16  aryl, or ##STR23##  wherein B is a C 1  -C 18  alkyl or a C 6  -C 16  aryl, and those conforming to ##STR24## wherein R 4  independently denotes a C 6  -C 16  aryl, a C 2  -C 12  alkenyl or a C 1  -C 32  alkyl and   R 3  denotes a C 2  -C 18  alkyl, >C═O, a dialkylsilyl, ##STR25##  where A is a C 1  -C 20  alkyl or a C 6  -C 16  aryl, or a ##STR26##  where B is a single bond, C 6  -C 20  aryl or a C 1  -C 20  alkyl, and those conforming to ##STR27## wherein R 5  independently denotes a C 1  -C 8  alkyl, C 7  -C 18  alkaryl, a hydrogen atom or an alkali metal, or ##STR28##  where B is a C 1  -C 18  alkyl or a C 6  -C 16  aryl, or ##STR29##  where A is a C 1  -C 12  alkyl or a C 6  -C 16  aryl and R 6  denotes a single bond, a C 1  -C 12  -alkyl or C 6  -C 16  aryl.   
     
     
       7. A molding composition comprising (a) a bisphenol A based homopolycarbonate and (b) di-(2-phenyl-1,3,4-oxadiazolone-[5])-4-terephthalamide. 
     
     
       8. A molding composition comprising (a) a bisphenol A based homopolycarbonate and (b) N,N'-bis(2-phenyl-1,3,4-oxadiazolone-(5))-urea. 
     
     
       9. The composition of claim 7 further comprising glass fibers. 
     
     
       10. A molding composition comprising (a) a bisphenol A based homopolycarbonate and (b) 4,4'-diphenoxycarbonyl-bis-alpha,beta-(1,3,4-oxadiazolone-[5]-yl)ethane. 
     
     
       11. The molding composition of claim 1 wherein said thermoplastic resin is selected from the group consisting of aromatic polyester, aromatic polyester carbonates and thermotropic liquid crystalline resins. 
     
     
       12. A molding composition comprising (a) a polycarbonate resin and (b) about 0.1 to about 25% relative to the weight of said (a) plus (b) of a chemical blowing agent selected from the group consisting of compounds conforming to ##STR30## wherein R 1  is a C 6  -C 16  aryl, a C 1  -C 32  alkyl, or a C 2  -C 12  alkenyl, and R 2  is a C 1  -C 20  alkyl, C 7  -C 20  alkaryl, trialkylsilyl, a hydrogen atom, an alkali metal or ##STR31## where A is C 1  -C 12  alkykl or C 6  -C 16  aryl, or ##STR32## wherein B is a C 1  -C 18  alkyl or a C 6  -C 16  aryl, and those conforming to ##STR33## wherein R 4  independently denotes a C 6  -C 16  aryl, a C 2  -C 12  alkenyl or   a C 1  -C 32  alkyl and   R 3  denotes a C 2  -C 18  alkyl, ##STR34## a dialkylsilyl, ##STR35## where A is a C 1  -C 20  alkyl or a C 6  -C 16  aryl, or a ##STR36## where B is a single bond, C 6  -C 20  aryl or a C 1  -C 20  alkyl, and those conforming to ##STR37## wherein R 5  independently denotes a C 1  -C 8  alkyl, C 7  -C 18  alkaryl, a hydrogen atom or an alkali metal, or ##STR38## where B is a C 1  -C 18  alkyl or a C 6  -C 16  aryl, or ##STR39## where A is a C 1  -C 12  alkyl or a C 6  -C 16  aryl and R 6  a single bond, a C 1  -C 12  alkyl or C 6  -C 16  aryl.